Effective address in assembly

I am suppose to determine the effective address if the instruction below and the contents of any affected register (except the PC) or memory location after each of the instructions in problem is executed. Assume the initial state (in hex) of the CPU and memory before every instruction is as follows: Processor is MC68hc12.
ACCA = 00 ACCB = 05 IX = 0111 IY = 0100

I don't even know how to start the problem. From what I could find the effective address is the address of the data referred to in the instruction. My text book didn't even define effective address. Could someone provide a little explanation on this or point me to some simple explanation of the concept.

Each CPU type will have a slightly different machine language so you should first try to determine what commands the two instruction lines are executing. Typically CPUs take in instructions which contain the command type and command parameters, e.g. <command type> <parameter 1> <parameter 2>. Also, find out what the segment registers are, etc.

The latextlab site seems to be down any other suggestions for information. This is an assignment from the 1st chapter of a MC68hc12 book. It doesn't explain effective addressing, just uses the term. I'm totally lost.
Thanks for your help.

Effective address just means the actual address used for an instruction's operand, or when the address itself is the operand, as in the case of the Load Effective Address (LEA) instruction on Intel cpu's.